title: Role of diffusion in the external gas exchange of animals.
mesh_terms: D000663:Amphibians; D000828:Animal Population Groups / Q000502:physiology*; D000818:Animals; D001717:Birds; D002245:Carbon Dioxide / Q000378:metabolism*; D004058:Diffusion; D005399:Fishes; D006801:Humans; D007313:Insecta; D008168:Lung / Q000502:physiology; D010100:Oxygen / Q000378:metabolism*; D012119:Respiration
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen